"The path that the moon is taking through Earth's shadow is almost directly through [the shadow's] center, making for the longest possible path and so the longest duration," said Ben Burress, staff astronomer at the Chabot Space & Science Center in Oakland, California.

Earth's shadow started to darken the moon around 18:22 universal time, or UT (2:22 p.m. eastern time). The period when the moon is completely engulfed in Earth's shadow—known as totality—began at 19:22 UT and lasted for almost two hours.

"The last eclipse that was as long as this one was in 2000, while the next won't be until 2018, so this makes it a somewhat rare event."

Earth's shadow starts to take a "bite" out of the full moon during the June 15 total lunar eclipse, as seen from Lucknow, India. (Take a moon myths and mysteries quiz.)

From Indonesia to New Zealand, viewers saw the moon's face slowly eaten away by the initial stages of the lunar eclipse just before the moon set on June 16. Except for northern Scotland and Scandinavia, most of Europe as well as eastern South America and western Africa saw totality get underway around local moonrise.

The best locations for viewing the entire eclipse were eastern Africa, the Middle East, Central Asia, and the western tip of Australia, according to Burress.

This celestial event wasn't visible from North America, unfortunately for Canadian, Mexican, and U.S. eclipse hunters, who will have to wait until December 10, when western parts of the continent will be treated to the next lunar eclipse.

A bridge over the Dnieper River in Ukraine seems to point the way toward a partial lunar eclipse on June 15. During the event, the moon eventually became completely engulfed in Earth's shadow.

Because of the tilt of the moon's orbit around Earth, the full moon usually passes slightly above or below Earth's cone-shaped shadow, so no lunar eclipse occurs. Sometimes, however, the geometry is just right for the full moon to cross Earth's orbital plane. As all three bodies line up, the moon passes through Earth's shadow and we see a lunar eclipse.

Partial eclipses happen when the moon grazes Earth's shadow, while total eclipses occur when the whole moon passes through the shadow.

Photograph by Sergey Dolzhenko, European Pressphoto Agency

Rusty Moon

The almost fully eclipsed moon took on a rusty orange hue in the skies over Islamabad, Pakistan, on June 16.

"The redness of the moon during totality depends partly on global atmospheric conditions," Burress said. That's because the light we see coming from the moon is actually reflected sunlight.

During a total lunar eclipse, Earth blocks the pure white, direct light from the sun. But some indirect light passing through Earth's atmosphere still manages to reach the moon.

Since dust and gases in Earth's atmosphere filter blue wavelengths from sunlight, the remaining light is reddened. The moon will therefore appear to change from brilliant silver to between bright orange and blood red during a lunar eclipse.

Photograph by Aamir Qureshi, AFP/Getty Images

Red Moon Over Egg Castle

A red moon rises over Castel dell Ovo—or Egg Castle—in Italy during the June 15 total lunar eclipse.

Thanks to the SLOOH "space camera," a robotic telescope in the Canary Islands, online sky-watchers around the world were able to witness the total lunar eclipse via Google's YouTube video site.